Extended optical range system for monitoring motion of a member

ABSTRACT

A system and method for monitoring a physiological parameter includes a garment that includes a fabric that exhibits both a light transmission property and a light reflection property. The amount of light transmitted through the fabric relative to the amount of light reflected by the fabric changes when the fabric stretches in response to motion, such as the motion induced by physiological activity (e.g., heart rate). The system includes at least one source of radiation having wavelength(s) in the range of 400 to 2200 nanometers and at least one detector responsive to such incident radiation. The source and detector are associated with the fabric such that the reception of incident radiation by the detector is directly affected by a change in the amount of light transmitted through the fabric relative to the amount of light reflected by the fabric when the fabric stretches. A signal processor converts a signal from the detector into a signal representative of at least one predetermined physiological parameter of a wearer of the garment.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of U.S. Ser. No.10/937,120, filed Sep. 9, 2004, now U.S. Pat. No. ______.

Subject matter disclosed herein is related to the following co-pendingapplications from which priority is claimed:

System for Monitoring Motion of a Member, U.S. Application No.60/502,760; (LP-5345USPRV), filed Sep. 12, 2003 in the name of Chia Kuoand George W. Coulston;

Blood Pressure Monitoring System and Method, U.S. Application No.60/502,751; (LP-5347USPRV), filed Sep. 12, 2003 in the names of GeorgeW. Coulston and Thomas A. Micka;

Reflective System for Monitoring Motion of a Member, U.S. ApplicationNo. 60/502,750; (LP-5346US PRV), filed Sep. 12, 2003 in the name ofGeorge W. Coulston;

Blood Pressure Monitoring System and Method Having Extended OpticalRange, U.S. Application No. 60/526,187; (LP-5622USPRV), filed Dec. 2,2003 in the names of George W. Coulston and Thomas A. Micka;

Extended Optical Range Reflective System for Monitoring Motion of aMember, U.S. Application No. 60/526,429; (LP-5621 USPRV), filed Dec. 2,2003 in the name of George W. Coulston; and

Extended Optical Range System for Monitoring Motion of a Member, U.S.Application No. 60/526,188; (LP-5620USPRV), filed Dec. 2, 2003 in thename of Chia Kuo and George W. Coulston.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a fabric useful in a system for monitoringmotion, such as the motion generated by a geometric change in a body inresponse to physiological activity.

2. Description of the Prior Art

Heart rate monitors are known for measuring and reporting the heart beatof humans and animals. Such monitors receive signals from the pulsatingflow of blood synchronized with the periodic pumping activity of theheart. Typically, the known monitors detect the pulsating flow of bloodthrough a sensor in a chest belt or through a sensor clippedmechanically to an ear or finger. U.S. Pat. No. 5,820,567 (Mackie)describes a representative arrangement of a chest belt or an ear clipfor a heart rate sensing apparatus.

A chest belt is difficult to fit and often requires gel to wet thesensor electrodes prior to use. Tight chest belts for heart monitoringcan be uncomfortable if worn for a prolonged period. Mechanical sensorsthat clip to a finger or an ear can also be uncomfortable.

The QuickTouch™ heart monitor sold by Salutron Inc. (Fremont, Calif.94538, USA) eliminates the chest strap, finger or ear clip to measureheart rate in all phases of exercise. However, while eliminatingcumbersome wires and straps, two points of body contact are required inoperation. This device thus requires application of two fingers on awatch band, two hands on a treadmill, or two hands on a bicycle handlebar to give heart rate readings. As a result, this device does nottotally free the subject from the monitoring process.

Systems that relieve the monitored subject from the discomfort of chestbelts or clip devices to the finger or ear, and from the inconvenienceof being restricted to the monitoring apparatus, have been disclosed.

U.S. Pat. No. 6,360,615 (Smela) discloses a monitoring system using agarment that detects motion in the body of the wearer through a straingauge implemented using a polypyrrole-treated fabric.

U.S. Pat. No. 6,341,504 (Istook) discloses a garment for physiologicalmonitoring comprising one or more elongated bands of elastic materialwith conductive wire formed in a curved pattern. When the garment isworn by a human, the elongation and relaxation of the fabric caused bygeometrical changes of the human frame induce electrical propertychanges in the conductive wire(s) of the garment. Such a system adds anadditional component of complexity to the fabric structure, which is notwell-suited to traditional garment design and construction.

U.S. Pat. No. 4,909,260 (Salem) describes a bulky waist belt system forphysiological monitoring.

U.S. Pat. No. 5,577,510 (Chittum) describes bulky chest and waist beltsfor physiological monitoring.

Patent Publication WO 9714357, Healthcare Technology Limited, GreatBritain, discloses a monitor capable of generating an audio heartbeatmessage.

SUMMARY OF THE INVENTION

The present invention is directed to a fabric, garment, overall systemand method for monitoring motion of a member, and is believedparticularly useful for monitoring motion generated by geometric changesof the body of a subject in response to physiological activity. Bymonitoring such motion, a noninvasive measurement of a parametercharacterizing the physiological activity may be derived.

The fabric can comprise a first plurality of reflective yarns knitted orwoven with a second plurality of stretchable yarns. The fabric exhibitsboth a light transmission property and a light reflection property whenthe fabric is illuminated with light having a wavelength in the range offrom about 400 nanometers to about 2200 nanometers, and particularly inthe ranges from about 400 to about 800 nanometers and from about 700 toabout 2200 nanometers.

The amount of light transmitted through the fabric relative to theamount of light reflected by the fabric changes as the fabric stretchesand recovers in response to motion, such as the motion induced geometricchanges in a human body caused by physiological activity.

In the preferred instance each reflective yarn has a coating of anelectrically conductive, specularly reflective material thereon, andeach stretchable yarn is formed as a combination of a covered elasticyarn and a hard yarn.

The fabric may be used as a monitoring patch in a garment or textilemantle.

The garment or textile mantle having the patch of monitoring fabricdisposed thereon or therein may be incorporated into a system formonitoring motion, such as the motion generated by geometric changes inthe body of a subject due to physiological activity. The system furtherincludes at least a source providing radiation with wavelength(s) in therange from about 400 nanometers to about 2200 nanometers, andparticularly in the ranges from about 400 to about 800 nanometers andfrom about 700 to about 2200 nanometers. The system still furtherincludes at least a detector responsive to incident radiation in thesame wavelength range and sub-ranges. The source and the detectorpreferably are attached to the fabric in predetermined positions suchthat the reception of incident radiation by the detector is directlyaffected by a change in the amount of radiation either transmittedthrough the fabric or reflected by the fabric, depending on thearrangement of the radiation source and radiation detector. Such changesoccur when the fabric stretches in response to motion due to geometricchanges in the body of the subject S wearing the garment or in the bodycomponent having the mantle thereon. A signal processor converts thesignal received from the detector into a signal representative of atleast one predetermined physiological parameter of the subject wearingthe garment or mantle.

Alternatively, the system can comprise more than a single radiationsource and more than a single radiation detector for each source. Insuch an alternative embodiment, the signal processor is responsive tosignals from more than a single radiation source and more than a singleradiation detector and converts these signals into a signalrepresentative of one or more predetermined physiological parametersassociated with the subject wearing the garment.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be more fully understood from the following detaileddescription, taken in connection with the accompanying drawings, whichform a part of this application, and in which:

FIG. 1 is a stylized pictorial representation of a system for monitoringat least one physiological parameter of a subject S that includes agarment sized to be worn over the torso of the subject S;

FIGS. 2A and 2B are diagrammatic views illustrating the operation of themonitoring system of the present invention when operating in the lightreflection mode;

FIG. 2C is a graphical representation of the change in the amount oflight transmitted through a fabric relative to the amount of lightreflected by the fabric as the fabric stretches and recovers;

FIG. 2D is a graphical representation of a signal, periodic in time,representing the change in the amount of light transmitted through thefabric relative to the amount of light reflected by the fabric duringstretching and recovery of the fabric;

FIGS. 3A and 3B are diagrammatic views illustrating the operation of themonitoring system of the present invention when operating in the lighttransmission mode,

FIG. 3C is a graphical representation of the change in the amount oflight transmitted through the fabric relative to the amount of lightreflected by the fabric as the fabric stretches (i.e., elongates andrecovers);

FIG. 3D is a graphical representation of a signal, periodic in time,representing the change in the amount of light transmitted through thefabric relative to the amount of light reflected by the fabric duringstretching cycles (consecutive elongation and recovery) of the fabric;

FIG. 4A is a time diagram of the waveform of the raw signal produced bythe described Example of the invention;

FIG. 4B is the frequency domain spectrum of the waveform of FIG. 4A;

FIGS. 4C and 4D are waveforms representative of physiological parametersof the subject derived from the waveform of FIG. 4A; and

FIG. 4E is a graphical representation of the amount of light transmittedthrough a fabric relative to the amount of light reflected by the fabricin each of three discrete elongation stages of fabric stretch.

DETAILED DESCRIPTION OF THE INVENTION

Throughout the following detailed description similar referencecharacters refer to similar elements in all figures of the drawings.

FIG. 1 is a stylized pictorial representation of a motion monitoringsystem 10 in accordance with the present invention as applied to thetask of monitoring motion due to geometric changes of the body of asubject S in response to physiological activity. A noninvasivemeasurement of one or more parameter(s) characterizing the physiologicalactivity of the subject S may be derived by monitoring such motion(s).

As seen in FIG. 1, the system 10 includes a garment 12 having at least aportion, or patch 14, formed from a monitoring fabric 16. The monitoringfabric 16 has an exterior or outer surface 16E presented to a viewer andan interior surface 161 presented to the body of the subject S. Thepatch 14 of the monitoring fabric 16, although shown as rectangular inFIG. 1, may take any convenient shape. For example, the patch may becircular, oval in shape, or may be any regular or irregular shape. Ifdesired, a portion or even the entirety of the garment 12 may be madefrom the monitoring fabric 16.

The monitoring fabric 16 in accordance with the present inventionexhibits both a light transmission property and a light reflectionproperty when the fabric is illuminated with light having wavelength(s)in the extended range from about 400 to about 2200 nanometers. Thisrange is extended in the sense that it encompasses both light withwavelengths in the near infrared spectrum and broad spectrum white lighthaving wavelengths in the visible spectrum.

As used herein the term “broad spectrum white light” means light havinga wavelength in the range from about four hundred (400) nanometers toabout eight hundred (800) nanometers.

As used herein the term “near infrared light” means light having awavelength in the range from about seven hundred (700) nanometers toabout twenty two hundred (2200) nanometers. The wavelength of 805nanometers or the wavelength of 880 nanometers may be used in systemsoperating in the near infrared spectrum. The wavelength of 805nanometers is preferred.

In accordance with the present invention the amount of light transmittedthrough the fabric 16 relative to the amount of light reflected by thefabric 16 is able to change when the fabric stretches. The stretchingmay be in response to geometric changes of the body of the subject S dueto the occurrence of predetermined physiological activities on or withinthe body of the subject S, such as but not limited to, heart rate,respiration rate, blood pressure, and the like. The term “light balance”may be used herein to refer to the amount of light transmitted throughthe fabric 16 relative to the amount of light reflected by the fabric16.

The monitoring fabric 16 used in the patch 14 can be made fromreflective yarns, stretchable yarns or any combination of reflective andstretchable yarn or any like material. In one exemplary construction afirst plurality of reflective yarns is combined with a second pluralityof stretchable yarns.

The yarns can be combined in any conventional manner including woven ornon-woven construction.

For woven constructions, yarns can be combined in plain weave, satinweave, twill weave or any other well known constructions. Woven fabricsmay also include weft elastic, warp elastic or bielastic woven fabricsfor varying fabric elasticity.

For non-woven constructions such as knit constructions, yarns can becombined by circular knit, warp knit or any other suitable knitconstruction. In circular knits, typical constructions are single jersey(i.e., different structure in front and back, e.g. 1×1 knit) and doublejersey (i.e., same structure in front and back, e.g. 2×1 knit). Thestitch size and distance determine the openness of the knit fabric. Warpknits may include tricot and raschel constructions where the tightnessis determined by the number of needles/inch or the stitch size.

Any suitable apparel denier and any suitable needle combination orwarp/weft intensity may be used in making the monitoring fabric. Eachreflective yarn may comprise a coating of a specularly reflectivematerial thereon. The coating may also be electrically conductive.Furthermore, the reflective yarn may be elastic or include an elasticcomponent. Each stretchable yarn is formed as a combination of anelastic yarn component and a hard yarn component.

In the preferred instance the reflective yarn is that yarn sold by LairdSauquoit Technologies, Inc. (300 Palm Street, Scranton, Pa., 18505)under the trademark X-static® yarn. X-static® yarn is based upon a 70denier (77 dtex), 34 filament textured nylon available from INVISTANorth America S. á r. I., Wilmington, Del. 19805, as product ID70-XS-34×2 TEX 5Z that is electroplated with electrically-conductivesilver.

Alternatively, another method of forming the monitoring fabric 16 is toscreen-print a pattern using an electrically conductive ink afterconstructing the yarns in any conventional woven or non-woven manner.Suitable electrically conductive inks include, but are not limited to,those sold by DuPont Microcircuit Materials, Research Triangle Park,N.C. 27709, as silver ink 5021 or silver ink 5096, and the like.

A screen-printed pattern of conductive inks must also allow the fabricto move. Preferably, the conductive ink does not affect the ability ofthe fabric to stretch and recover. One way to prevent affecting thestretch and recovery properties of fabric is to screen-print a patternof conductive ink(s) in the form of a matrix of dots. Such a dot matrixpattern provides full freedom of movement for the yarns in the fabric,while still exhibiting desired light reflection and transmissionproperties.

The patch 14 of monitoring fabric 16 can alternatively be formed fromelastic and electrically conductive composite yarn comprising a coreyarn made of, for instance, LYCRA® spandex yarn wrapped with insulatedsilver-copper metal wire obtained from ELEKTRO-FEINDRAHT AG,Escholzmatt, Switzerland, using a standard spandex covering process. Thecore yarn may further be covered with any nylon hard yarn or polyesterhard yarn.

Stretchable yarn can be formed in any conventional manner. For example,the stretchable yarn can be formed as a combination of a covered elasticyarn and a hard yarn.

In one preferred embodiment, the covered elastic yarn can be comprisedof a twenty (20) denier (22 dtex) LYCRA® spandex yarn single-coveredwith a ten (10) denier (11 dtex) seven filament nylon yarn. LYCRA®spandex yarn is available from INVISTA North America S. á r. I.,Wilmington, Del. 19805. Alternatively, the elastic yarn component of thepresent invention may comprise elastane yarn or polyester bicomponentyarns such as those known as ELASTERELL-P™ from INVISTA S. á r. I. NorthAmerica Inc. of Wilmington, Del. The terms spandex and elastane are usedinterchangeably in the art. An example of a branded spandex yarnsuitable for use with the present invention is LYCRA®.

Synthetic bicomponent multifilament textile yarns may also be used toform the elastic yarn component. One preferred synthetic bicomponentfilament component polymer can be thermoplastic. The syntheticbicomponent filaments can be melt spun or formed in any other mannercommon in the art of filament formation. In the most preferredembodiment the component polymers can be polyamides or polyesters.

A preferred class of polyamide bicomponent multifilament textile yarnscomprises those nylon bicomponent yarns which are self-crimping, alsocalled “self-texturing.” These bicomponent yarns comprise a component ofnylon 66 polymer or copolyamide having a first relative viscosity and acomponent of nylon 66 polymer or copolyamide having a second relativeviscosity, wherein both components of polymer or copolyamide are in aside-by-side relationship as viewed in the cross section of theindividual filament. Self-crimping nylon yarn such as that yarn sold byINVISTA North America S. á r. I., Wilmington, Del. 19805 under thetrademark TACTEL® T-800™ is an especially useful bicomponent elasticyarn.

Some examples of polyester component polymers include polyethyleneterephthalate (PET), polytrimethylene terephthalate (PTT) andpolytetrabutylene terephthalate. In one preferred embodiment, polyesterbicomponent filaments comprise a component of PET polymer and acomponent of PTT polymer in a side-by-side relationship as viewed in thecross section of the individual filament. One exemplary yarn having thisstructure is sold by INVISTA North America S. á r. I., Wilmington, Del.19805 under the trademark T-400™ Next Generation Fiber.

The hard component could be made from any inelastic synthetic polymerfiber(s) or from natural textile fibers, such as wool, cotton, ramie,linen, rayon, silk, and the like. The synthetic polymer fibers may becontinuous filament or staple yarns selected from multifilament flatyarns, partially oriented yarns, textured yarns, bicomponent yarnsselected from nylon, polyester or filament yarn blends. The hardcomponent is preferably 260 denier (286 dtex) 68 filament nylon yarn.

Nylon yarns may preferably comprise synthetic polyamide componentpolymers such as nylon 6, nylon 66, nylon 46, nylon 7, nylon 9, nylon10, nylon 11, nylon 610, nylon 612, nylon 12 and mixtures andcopolyamides thereof. In the case of copolyamides, especially preferredare those including nylon 66 with up to 40 mole percent of apolyadipamide wherein the aliphatic diamine component is selected fromthe group of diamines available from INVISTA North America S. á r. I.,Wilmington, Del. 19805 (Wilmington, Del., USA, 19880) under therespective trademarks DYTEK A® and DYTEK EP®.

Further in accordance with the present invention, the hard yarn portionof the present invention may comprise polyesters such as, for example,polyethylene terephthalate, polytrimethylene terephthalate, polybutyleneterephthalate and copolyesters thereof.

The monitoring fabric 16 may also be formed from composite yarns inwhich the reflective and stretchable components are combined in the sameyarn. Such a composite yarn would include a covering yarn having aspectrally reflective outer surface that is wrapped about an elasticyarn component in one or more layers.

The remainder of the structure of the garment 12, if not also formed ofthe monitoring fabric, may exhibit any convenient textile construction(e.g., knitting or weaving as described above) and may be made from anysuitable textile filament apparel denier yarn.

In one embodiment, the monitoring fabric 16 used in the patch 14 isattached to the garment 12. The patch 14 could be sewn, glued, stapled,taped, buttoned, interwoven or attached to the garment by any othermeans.

It alternatively lies within the contemplation of the invention that thegarment 12 may be formed entirely from the monitoring fabric 16. Anysuitable needle combination or warp/weft intensity may be used for thegarment 12.

In another embodiment, the garment is seamlessly constructed of themonitoring fabric 16 using any suitable needle combination into thematerial of the remainder of the garment 12. In this context the term“seamless” refers to the known process of circular knitting on aseamless knitting machine (e.g., from Santoni S.p.A., Brescia, Italy).Garments processed in this way may possess minor seams, for example, theshoulder portion of a vest or the crotch seam of panty hose may beformed using traditionally practiced seaming methods. For these reasonsthe “seamless” term of art includes garments with one, or only a fewseams, and substantially constructed from a single piece of fabric.

The system 10 shown in FIG. 1 is adapted for monitoring the motiongenerated by geometric changes of the body accompanying thephysiological activities of respiration or heart beat of the subject S.The garment 12 is thus configured similar to a vest or shirt, althoughother garment configurations are contemplated. For a vest-like orshirt-like textile structure, a contour and appropriate openings areformed for disposition on the torso of the subject S. For such use, thepatch 14 of monitoring fabric 16 should be located in a position ofmaximum sensitivity to geometric changes in the body of the subject S.For instance, the patch 14 could be used to monitor the beating heart orthe chest wall movement incident with respiration by disposing the patch14 beneath the nipple of the left breast of the subject S. It should beunderstood that the physical form of the garment may be appropriatelymodified for disposition over other parts of the body of the subject Sin the event it is desired to monitor the motion of another portion ofthe body.

The light balance is monitored as the monitoring fabric 16 stretches andrecovers. For this purpose, the system 10 further includes a suitablesource 18 of radiation operable in the wavelength range from about 400nanometers to about 2200 nanometers, and particularly in the wavelengthranges from about 400 to about 800 nanometers and from about 700 toabout 2200 nanometers. An associated detector 22 is responsive toincident radiation in the given wavelength range and sub-ranges forproducing signals in response thereto.

In the case of operation with near infrared light, the radiation source18 can be a compound semiconductor-based (e.g., gallium arsenide orgallium aluminum arsenide) photo-emitting diode operating in theinfrared range (at a wavelength of 805 nanometers or 880 nanometers) orany similar radiation source. The radiation detector 22 can be anydevice that can detect radiation, for instance, a photodiode coupled toappropriately configured output amplification stages. Any well knownsemiconductors can be used for forming the photodiode, including siliconor germanium. A commercially available radiation source and detectorpackage suitable for use in the system of the present invention is thatavailable from Fourier Systems Ltd. (9635 Huntcliff Trace, Atlanta, Ga.,30350) as model DT155 (0-5 volt output).

For broad spectrum white light (400 to 800 nanometers) operation, thesource 18 can be a compound semiconductor-based “white LED” (e.g., alight emitting diode employing an indium gallium nitride based devicewith suitable phosphors to provide broad spectrum white light emission).The detector 22 is preferably a silicon phototransistor coupled toappropriately configured output amplification stages.

The radiation source 18 and the detector 22 are attached to monitoringfabric 16 in predetermined relative positions. The positions weredetermined such that the reception of incident radiation by the detector22 is directly affected by a change in the amount of light transmittedthrough the monitoring fabric 16 relative to the amount of lightreflected by the monitoring fabric 16 when the fabric stretches andrecovers. In the preferred case, the radiation source 18 and detector 22are embedded, or fixed firmly, into the textile structure of themonitoring fabric 16. The radiation source 18 and detector 22 can befixed using any well known attachment method, including but not limitedto, clamping, gluing, sewing, taping, or hook and loop fasteners(Velcro). Optionally, it may be desirable in some operationalconfigurations of the invention (e.g., when the subject S is on atreadmill) to dispose both the source and the detector remote from andnot in direct contact with the fabric 16. In such a remote arrangement,the radiation source 18 and detector 22 could be located in anyarrangement that permits the detector 22 to detect changes in thetransmission and reflection of radiation during stretching and recovery.

In the operational configuration shown in FIG. 1 (and discussed morefully in connection with FIGS. 2A and 2B) both the source 18 and thedetector 22 are mounted to the exterior surface 16E of the patch 14 ofmonitoring fabric 16. Alternatively, as discussed in connection withFIGS. 3A and 3B, one of the source 18 or the detector 22 is mounted tothe exterior surface 16E of the patch 14 of monitoring fabric 16 whilethe other of the detector 22 or the source 18 is mounted to the interiorsurface 161 of the patch 14 of the monitoring fabric 16.

A suitable electrical source 26 for the radiation source 18 may beconveniently carried in the garment 12. The electrical source 26 can beany conventional electrical source known in the art including, but notlimited to, a battery.

The system 10 may further comprise a signal acquisition and storage unit28 coupled to the detector 22 for storing signals produced thereby inresponse to incident radiation. Electrically conductive paths 32 areprovided in the garment 12 to interconnect the infrared source 18, thedetector 22, the electrical source 26 and the signal storage unit 28 inany appropriate electrical configuration.

One convenient manner of forming the conductive paths 32 is to knit orweave conductive filaments into the garment 12. A suitable conductivefilament for such use is the X-static® yarn mentioned earlier.Alternatively, the wires could be arranged so as to be unattached to thefabric.

Another method of forming the conductive paths 32 is to screen-print thepattern of conductive paths using an electrically conductive ink. Anyconductive ink could be used including, for instance, electricallyconductive inks sold by DuPont Microcircuit Materials, Research TrianglePark, N.C. 27709, as silver ink 5021 or silver ink 5096. Silver ink 5021ink is useful in fabricating low voltage circuitry on flexiblesubstrates, while silver ink 5096 is suggested for use in situationswhere extreme crease conditions are encountered. While silver ink 5021has a higher conductivity, silver ink 5096 is more easily spread andmore easily builds bridges among the fibers of the fabric of the garment12.

Once the signal is received by the radiation detector 22, a signalprocessor 34 may be used to convert the periodically varying signaloutput from the detector 22 representative of incident radiation thereoninto a signal representative of at least one (or a plurality) ofpredetermined parameter(s) (e.g., respiration rate, heart rate) of thesubject S wearing the garment 12. In the preferred instance the signalprocessor 34 comprises a suitably programmed digital computer. However,any signal processor known to those skilled in the art could be used.

The signals from the detector 22 stored within the storage unit 28 maybe transferred to the signal processor 34 in any convenient manner forconversion into signals representative of the physiological parameter(s)of the subject S. For example, transfer between the storage unit 28 andthe processor 34 may be effected by either a hardwired connection or athrough-space wireless (e.g., a wireless LAN using 2.4 GHz and 802.11a/bor 802.11g protocol known to skilled practitioners of the wireless highspeed data communications) or an optical transmission link, as suggestedin the area indicated by reference character 36 in FIG. 1.

The signal from detector 22 is a raw signal and comprises a composite offrequencies containing at least the respiration cycle and heart rate ofthe subject S. Certain noise sources contribute to the overall waveform.Such noise sources are believed to arise from extraneous motion of thesubject S or the monitoring fabric 16 and are not associated withrespiration and heart rate. These sources of noise could be filteredusing appropriate electronic filtering techniques. Specifically, highfrequency and low frequency pass filters appropriately chosen can createa cleaner raw overall waveform. Such filters could be selected accordingto methods known to those skilled in the art in order to obtain a signalassociated only with respiration or one associated only with heartbeat.Equivalently, filters to reduce known sources of signal noise are alsoeasily employed in the data acquisition system.

Although the signal processor 34 illustrated in FIG. 1 is disposed at alocation remote from the garment, it should be understood that it lieswithin the contemplation of the invention to implement the processor ina suitably sized package able to be physically mounted on the garment.In such an instance the output from the detector 22 may be directlybuffered into appropriate memory within the processor 34.

The operation of the motion monitoring system of the present inventionin the reflection mode may be more clearly understood with reference toFIGS. 2A through 2D. As noted earlier, in the reflection mode ofoperation both the source 18 and the detector 22 are mounted on oradjacent to the same surface of the monitoring fabric 16, typically theexterior surface 16E.

The source 18 is arranged in such a way as to maintain its relativeposition to the detector 22. For instance, the source 18 and detector 22may be rigidly connected together on one side of the monitoring fabric16 to maintain a spatial relationship. Alternatively, the position ofthe source relative to the detector can be maintained on opposite sidesof the monitoring fabric 16 for monitoring transmission. In such anembodiment, the radiation source 18 is connected to the radiationdetector 22 using a “clothes-pin” or alligator style clamp. Any wellknown means of maintaining the spatial relationship of the source 18relative to the detector 22 could be used.

The operation is discussed in the context of monitoring the periodicphysiological activity of respiration. FIG. 2A illustrates the fabric 16in an unstretched state, while FIG. 2B illustrates the fabric 16 in astretched state. The stretching illustrated in FIG. 2B can be caused bymovements such as the periodic physiological activity of respiration. Itshould be noted that FIGS. 2A and 2B are schematic and are not drawn toscale. For instance, though only two dimensional movement of the fabricis shown, movement in all directions is contemplated. As discussedabove, any extraneous motions of the subject S or monitoring fabric 16could be filtered as noise using appropriate electronic filteringtechniques.

As represented in FIG. 2A, in the unstretched state the filamentsforming the yarns 16Y of the monitoring fabric 16 lie within arelatively close distance of each other to define a pattern ofrelatively narrow gaps 16G. A generally circular spot indicated by thereference character 17 represents the area of the monitoring fabric 16illuminated by the source 18. Using appropriate optics (e.g., anobjective lens on the source 18) the size of the spot 17 may beadjustably selectable to focus on an area containing any arbitrarynumber of yarns 16Y forming the fabric 16 or down to an area containingonly a single filament of a yarn 16Y.

The radiation detector 22 can be arranged on the same side of themonitoring fabric 16 to receive radiation (so called “reflection mode”)or the detector 22 can be arranged to on the opposite side of themonitoring fabric 16 to receive transmitted radiation (so called“transmission mode”). Of the photons emitted from the source 18 towardthe surface 16E of the fabric 16, some photons are absorbed (e.g.,represented by a ray 18C) by the filaments 16F of the fabric while otherphotons (e.g., the rays 18A and 18B) pass through gaps 16G therein. Allof these photons (18A, 18B, 18C) are lost to the detector 22 if thesource 18 and detector 22 are arranged in reflection mode. In such anarrangement, the major portion of the light (e.g., represented by therays 18D through 18G) is reflected from the surface 16E of themonitoring fabric 16 toward the detector 22 when the fabric is notstretched. This major portion of the light is useful in producing acorresponding output signal from the detector 22.

As seen from FIG. 2B, as the fabric stretches, the size of the gaps 16Gformed in the monitoring fabric 16 increases. This increase in size ofthe gaps 16G increases the likelihood that a photon will pass throughthe fabric 16 (and be lost to the detector arranged in reflection mode),and decreases the likelihood that a photon will usefully reflect towardthe detector 22. The total number of photons lost to the detector 22 bytransmission through the fabric (e.g., represented by the rays 18A, 18B,18G and 18F) increases and the signal output from the detector 22 inreflective mode concomitantly decreases. Although the number of photonsabsorbed (e.g., represented by the ray 18C) does not necessarily change,the amount of yarn 16Y within the spot size 17 decreases, and it becomesless likely that a photon will strike yarn 16Y and be reflected orabsorbed.

As the body of the subject S contracts during an exhalation, the fabric16 undergoes the elastic recovery phase of its stretch. The gaps 16Greturn to their original size (FIG. 2A). A relatively large portion ofthe light is again usefully reflected toward the detector 22, increasingthe output signal therefrom.

Viewed consecutively these events define a stretch cycle of elongationand recovery. The signal generated at the detector 22 of the monitoringsystem varies from an initial state to an intermediate state and back tothe initial state, as represented by FIG. 2C. This figure graphicallyillustrates that during the course of a stretch cycle the light balance(reference character “LB” in FIG. 2C) of the fabric changes. Comparisonbetween the initial and inhalation states (indicated by respectivereference characters “I” and “II” in FIG. 2C) and between the inhalationand exhalation states (indicated by respective reference characters “II”and back to “I” in FIG. 2C) clearly shows that the amount of lightreflected by the monitoring fabric 16 changes in a periodic fashion overtime as the fabric stretches. In FIG. 2C, at the initial state (“I”) thereflected light represented by the bottom portion below the “LB” isgreater than the transmitted light represented by the upper portionabove the “LB”. In contrast, at the inhalation state (“II”) thereflected light represented by the bottom portion below the “LB” is lessthan the transmitted light represented by the upper portion above the“LB”.

This periodic variation in light balance is represented by FIG. 2D as atime-varying signal from “I” to “II” to “I” synchronized with theelongation and recovery stages of fabric stretch. This signal can be atemporal measure of the underlying physiological processes, whichprovide the forces causing the elongation and recovery.

Alternatively, the system 10 may operate in a light transmission mode asrepresented by FIGS. 3A, 3B. As in FIGS. 2A and 2 B, the illustrationsare schematic and are not drawn to scale. In the transmission mode ofoperation the source 18 and the detector 22 are disposed on oppositesides of the monitoring fabric 16. The operation is again discussed inthe context of monitoring respiration.

When the fabric 16 is not stretched (FIG. 3A), only a relatively smallportion of the light from the source 18 illuminating the spot 17 passesthrough gaps 16G in the fabric 16. As a result the number of photons(e.g., represented by rays 18A and 18B) incident on the detector 22 anduseful to produce a signal therefrom is concomitantly low. Photonsreflected from the fabric 16 (e.g., represented by the rays 18D through18G) or photons absorbed by the fabric filaments 16F (e.g., representedby the ray 18C) are lost, and thus contribute nothing to the output ofthe detector 22.

However, when the fabric 16 elongates due to motion in the body of thesubject S during an inhalation (as represented in FIG. 3B) the number ofphotons transmitted through the gaps 16G in the fabric increases (e.g.,represented by the rays 18A, 18B, 18G and 18F) since the illuminationspot size 17 remains constant. This increase in the number of usefulphotons falling upon the detector 22 changes its output accordingly.Some of the photons from source 18 are reflected (e.g., represented bythe rays 18D and 18E) or absorbed (e.g. represented by the ray 18C) andare lost, and so contribute nothing to the output of the detector 22.

The change in light balance LB is graphically represented in FIG. 3C.Again, for simplicity of discussion the portion of the total lightbudget absorbed by the fabric is ignored.

As represented by FIG. 3C the signal generated at the detector 22 variesfrom an initial state to an intermediate state and back to the initialstate as the fabric undergoes a stretch cycle of elongation from aninitial state followed by recovery. The change in light balance of thefabric during the course of a stretch cycle is again graphicallyillustrated in FIG. 3C. Comparison between the initial and inhalationstates (indicated by respective reference characters “I” and “II” inFIG. 3C) and between the inhalation and exhalation states (indicated byrespective reference characters “II” and back to “I” in FIG. 3C) clearlyshows that the amount of light transmitted through the fabric 16relative to the amount of light reflected by the fabric 16 changes in aperiodic fashion over time as the fabric stretches. (In the transmissionmode case, light lost to the detector due to absorption contributes tothe “reflected light” section of the graph.) Thus, in FIG. 3C in theinitial state (“I”) the reflected light represented by the bottomportion below the “LB” is greater than the transmitted light above the“LB”, and in the inhalation state (“II”), the reflected lightrepresented by the bottom portion below the “LB” is less than thetransmitted light above the “LB”.

This periodic variation in light balance is represented by FIG. 3D as atime-varying signal from “I” to “II” to “I” synchronized with theelongation and recovery stages of fabric stretch, and provides atemporal measure of the underlying physiological processes which providethe forces causing the elongation and recovery.

As in the case of the signal of FIG. 2C, this signal representing thechange in light balance LB is used to derive a signal representative ofthe physiological parameter of a subject S wearing the garment 12.

Those skilled in the art will also recognize that the principlesunderlying the invention as heretofore described can be applied in avariety of other situations where it is desired to monitor the motion ofa member. For example, in another embodiment the motion monitoringsystem of the present invention may be used to monitor movement of acomponent of a multicomponent structure.

The motion monitoring system for such a usage comprises a textilemantle, at least a portion of which is formed from the monitoringfabric. The term “textile mantle” encompasses any fabric structurecovering (in whole or in part) a component of a structure.

The textile mantle is disposed in any convenient manner over thecomponent whose motion is to be monitored. In the same way as heretoforediscussed the source 18 and a detector 22 are attached to the textilemantle in relative positions such that the reception of incidentradiation by the detector 22 is directly affected by a change in theamount of light transmitted through the fabric 16 relative to the amountof light reflected by the fabric 16 when the fabric 16 undergoes astretch cycle in response to motion of the component.

EXAMPLES OF THE INVENTION Example 1

A garment 12 substantially as depicted in FIG. 1 was constructed todemonstrate the principles of the invention. The garment 12 having anintegral patch 14 of monitoring fabric 16 was constructed using aeight-feed circular knitting machine, such as a Santoni SM8-8TOP. Thepatch 14 was located just below the left nipple on the chest. Themonitoring fabric 16 defining the patch portion 14 was constructed usingfour ends of reflective conductive yarns and four ends of a stretchableyarn. Each end of reflective conductive yarn was an X-Static® yarn asdescribed earlier. Each end of stretchable yarn was formed as acombination of a soft component and a hard component. The soft componentcomprised a twenty (20) denier (22 dtex) LYCRA® spandex yarnsingle-covered with a ten (10) denier (11 dtex) seven filament nylonyarn. The hard component comprised a 260 denier (286 dtex) 68 filamentnylon yarn. The remainder of the garment 12 was constructed of coveredLYCRA® spandex yarn and nylon combination yarns supplied to all eightfeeds of the circular knitting machine; no reflective yarn was fed tothe machine. The knitting machine speed was forty-nine (49) revolutionsper minute, and the garment was produced directly in wearable form.

The source 18 and detector 22 were arrayed in the transmission mode asdepicted in FIGS. 3A and 3B. The source 18 and the detector 22 wereconfigured using the single package acquired from Fourier Systems Ltd.Huntcliff Trace, Atlanta, Ga., 30350) as DT155 with an output of zero tofive (0-5) volts. The wavelength used was 805 nanometers.

The DT155 source/detector package was clipped directly to the patch 14.The output from the detector 22 was directed to a signal acquisitionunit acquired from Fourier Systems Ltd. known as the “MultiLog Pro”.This signal acquisition unit included an on-board battery package. Thedata acquisition unit included user-selectable detector signal samplingrate in order to best resolve the frequencies expected, i.e., the rateof the heart beat and the rate of the respiration of the subject. Sincethe expected frequencies were in the range of one hundred Hz or less, asignal sampling rate of fifty (50) Hz was selected.

The zero to five volts output signal from data acquisition unit wasdownloaded to a C600 laptop computer with a Mobile Pentium® III CPU, 750MHz, available from Dell Computer for signal processing.

A raw signal obtained from a subject S is shown in FIG. 4A. This signalis a composite of frequencies containing at least the respiration cycleand heart rate of the subject S. Certain noise sources contribute to theoverall waveform. Such noise sources are believed to arise fromextraneous motion of the subject S and fabric 16 and are not associatedwith respiration and heart rate. These sources of noise could befiltered using appropriate electronic filtering techniques.Specifically, high frequency and low frequency pass filtersappropriately chosen can create a cleaner raw overall waveform. Suchfilters could be selected accordingly by methods known to those skilledin the art in order to obtain a signal associated only with respirationor one associated only with heartbeat. Equivalently, filters to reduceknown sources of signal noise are also easily employed in the dataacquisition system.

The composite frequency waveform of FIG. 4A is resolvable into thefrequency domain spectrum shown in FIG. 4B by methods known to thoseskilled in the art. In this example the raw signal of FIG. 4A wasdownloaded to a computer and processed using a Fourier frequencydeconvolution algorithm.

The raw data of FIG. 4A [F(time) versus time] was expressed as inEquation 1.

$\begin{matrix}{{F(t)} = {a_{0} + {a_{n}{\sum\limits_{n = 1}^{\infty}{\sin \left( {2\pi \; {nft}} \right)}}}}} & (1)\end{matrix}$

where a_(n) reflects the relative magnitude of those signal componentswith frequency n (per minute) and

a₀ is zero frequency (“DC”) component.

The relative amounts of each expected frequency in the spectrum is givenby weighting coefficients (a_(n))) determined from Equation 2.

$\begin{matrix}{a_{n} = {\left( {2/L} \right){\int_{0}^{L}{{F(t)}{\sin \left( {2\pi \; {nft}} \right)}{t}}}}} & (2)\end{matrix}$

where L is a parameter affecting the frequency resolution to be achievedand selected by known methods.

In this case, the base frequency or lowest frequency (f) to be expectedwas chosen as one per minute. Any frequency greater than the basefrequency (nf; where n is an integer) was resolvable as a consequence.

Two predominating frequencies were found using these methods. Theseresults are represented by FIGS. 4C and 4D. FIG. 4C is the heart beatrate of 78 per minute, and FIG. 4D is the breathing rate of 18 perminute.

This result illustrates that a garment having a portion of monitoringfabric strategically located thereon can successfully report thebreathing (respiration) rate and heart rate of the garment wearer wherethe garment functions as part of a system according to the disclosuresherein.

The fabric used in this example was monitored using the DT155 source anddetector package attached to this fabric in the transmission mode ofoperation. The source and detector package had a zero to 5 volt range.The output from the detector was measured as a function of the fabricelongation in three discrete stages: relaxed; elongated by ten percentgreater than the relaxed state (ten percent stretch); and elongated bytwenty percent greater than the unstretched state (twenty percentstretch).

The measured detector voltage was the complement of the reflection plusthe absorption by the fabric. As a result, an increase in lighttransmission with increasing fabric elongation provided a decreasingvoltage. In the initial state the voltage was 3.64 volts (this outputmay be called the fabric bias voltage). At ten percent elongation, thevoltage was 3.36 volts, and at twenty percent elongation, the output was2.71 volts.

These results are graphically represented by FIG. 4E. FIG. 4Eillustrates that the amount of light transmitted through the monitoringfabric relative to the amount of light reflected by the monitoringfabric (i.e., the light balance) changes when the fabric stretches inresponse to motion.

Any program can be used to deconvolute the Fourier frequency. A program,written in Visual Basic language, useful for performing a Fourierfrequency deconvolution is as follows:

Sub find_an( ) ‘ ‘ findheartbeat Macro L = Cells(9, 7).Value   f =Cells(9, 5).Value   j = 12    avg = Cells(12, 5).Value ‘ avg = 0   For n= 1 To 95  an = 0  bn = 0   i = 4 kuo2: t1 = Cells(i, 1).Value   t2 =Cells(i + 1, 1).Value   y1 = Cells(i, 2).Value − avg   y2 = Cells(i + 1,2).Value − avg   an = an + 2 / L * (y1 * Sin(2 * 3.1416 * n * f * t1) +y2 * Sin(2 * 3.1416 * n * f * t2)) / 2 * (t2 − t1)   bn = bn + y1 + avg  If t2 > L Then   GoTo kuo1   Else   i = i + 1   GoTo kuo2   End Ifkuo1: Cells(j + n, 5).Value = an   Next n End Sub

Example 2

In this example, Example 1 was repeated substantially in the samemanner, except for the use of a source providing radiation at thewavelength of 880 nanometers. Substantially the same result wasachieved.

Example 3

Except for the following changes, Example 1 was repeated substantiallyin the same manner. A source (broad spectrum white light LED; a suitablesource is available from Lumitex® Inc., 8443 Dow Circle, Strongsville,Ohio 44136, USA; Part No. 003387) providing radiation in the wavelengthrange of 430 to 700 nanometers was used in combination with a siliconphototransistor detector and suitable amplification circuitry commonlyemployed in the art. A combined respiration and heart rate signal wasobtained. However, in this example the signal was not further processed,as in Example 1, to separately obtain heart and respiration rates.

Example 4

In this example, fabrics of different types and construction weremonitored using the DT155 source/detector package (with a zero to 5 voltrange) attached to the fabric in the transmission mode of operationexactly as in Example 1 of the invention. The output from the detectorwas measured with the fabric in an unstretched condition, also calledthe static fabric state. As before, the measured detector voltage wasthe complement of the reflection plus the absorption by the fabric.

In each measurement the static fabric state was characterized with avoltage signal from the detector. This output was called the fabric biasvoltage. A zero bias voltage meant total fabric transmission for the 805nanometer light from the source.

Simultaneously with the bias voltage measurement, a DT009 light sensorobtained from Fourier Systems Ltd. coupled with the “MultiLogPro” (as inExample 1) was used to measure visible light transmission through thefabric. This light transmission was measured as illuminance with adirect output in LUX (one LUX=one lumen per square meter). Theilluminance measurement with the DT009 light sensor measured lighttransmission of the fabric samples from a standard fluorescent desklamp, which provided light with wavelengths mostly in the spectral rangefrom 440 to 550 nanometers. The measured illuminance from the standardfluorescent desk lamp was 400 LUX incident on each sample. Theilluminance (LUX) transmitted by the fabric was a measure of theopenness of each sample. The data is reported in Table 1 below.

As is seen in Table 1, fabrics of different construction, compositionand thickness provide a range of visible light transmission and lightbalance (transmission, absorption and reflection) for light with an 805nm wavelength. A workable light balance can be achieved using a singlefabric layer, and will yield a good bias voltage, e.g. in the range of2.5 to 3.5 volts, in the static fabric state. The X-Static® yarn patchin a single layer of 1×1 knit fabric is one exemplary fabric that yieldsexcellent results. The X-Static® yarn 1×1 knit patch in a single layershows a 6.45 LUX visible light transmission and a bias of 3.17 volts.Table 1 sets out various fabrics tested and the correspondingilluminance and bias voltage observed.

TABLE 1 Illuminance Fabric/garment transmitted Bias voltage in sampledescription (LUX) static static condition Example 1 shirt One layer,0.023 177.0 0.0 outside reflective inch thickness X-Static ® yarn patchPolyester woven 2GT, no dye, 165.0 0.0 fabric one layer thick TommyJeans ® 100% cotton, 163.0 0.0 tee shirt one layer LYCRA ® nylon Knit,one layer 149.0 0.0 fabric Polyester woven 2GT, no dye, 109.0 0.0 fabrictwo layers thick Tommy Jeans ® 100% cotton, two 84.0 0.0 tee shirtlayers LYCRA ® nylon Knit, two layers 74.0 0.0 fabric LYCRA ® nylonKnit, one layer, 72.0 2.88 fabric conductive ink coated Example 1 shirtfour layers, 45.0 0.0 outside reflective 0.092 inch X-Static ® yarnthickness patch Example 1 shirt eight layers 16.4 1.50 outsidereflective X-Static ® yarn patch Polyester woven 2GT, woven, no 16.01.36 fabric dye, eight layers thick LYCRA ® nylon Knit, eight layers9.67 0.0 fabric Example 1 shirt 1 × 1 Knit, one 6.45 3.17 insidereflective layer X-Static ® yarn patch LYCRA ® nylon Knit, 16 layers2.34 3.50 fabric Example 1 shirt 2 × 1 Knit, one 0.88 3.77 insidereflective layer X-Static ® yarn patch Example 1 shirt 2 × 1 Knit, two0.58 3.89 inside reflective layers X-Static ® yarn patch Example 1 shirt1 × 1 Knit, two 0.29 3.96 inside reflective layers X-Static ® yarn patchExample 1 shirt 2 × 1 Knit, 4 layers 0.29 3.90 inside reflectiveX-Static ® yarn patch Example 1 shirt 1 × 1 Knit, 4 layers 0.0 3.85inside reflective X-Static ® yarn patch

It may be appreciated from the foregoing that the fabric, garment andsystem of the present invention provides a particularly usefulnoninvasive technique for the monitoring of one or more physiologicalparameters of a subject without necessitating a change of clothing orthe use of a chest or body strap or clamp. However, the fabric andsystem of the present invention also allow for the monitoring of anymovement that can be translated into the elongation and recovery ofelastic monitoring material.

When the fabric is in use, as when incorporated into a garment ormantle, the stretch cycle of elongation and retraction of the fabric inresponse to physiological activity of a subject wearing the garment or acomponent having the mantle thereon changes, or modulates, the amount oflight transmitted through the fabric relative to the amount of lightreflected by the monitoring fabric.

Those skilled in the art, having the benefit of the teachings of thepresent invention as hereinabove set forth, may effect modificationsthereto. Such modifications are to be construed as lying within thescope of the present invention, as defined by the appended claims.

1. A system for monitoring at least one predetermined physiologicalparameter of a wearer, comprising: a garment, at least a portion ofwhich garment is formed from a fabric having a first side defining anexterior surface and having a second side defining a wearer-contactinginterior surface when said garment is worn by the wearer, said fabrichaving a region thereof defining gaps of a first size between yarns whensaid fabric is stretched and defining gaps of a second size betweenyarns that is different from said first size when the fabric recoversfrom stretch in response to at least one predetermined physiologicalparameter of the wearer of the garment; at least one source of radiationhaving wavelength(s) in the range from about 400 to about 2200nanometers positioned external to the fabric to direct radiation ontothe exterior surface and onto the region; at least one detectorresponsive to incident radiation having wavelength(s) in the range fromabout 400 to about 2200 nanometers, to produce a signal representativethereof, with said detector mounted to either the first side or thesecond side of the fabric and external to the fabric, wherein the sourceand detector are associated with the fabric in substantially fixedrelative positions with respect to the region such that the reception ofincident radiation by the detector at a first time interval when thefabric is stretched as compared to the reception of incident radiationby the detector at a second time interval when the fabric recovers fromstretch is directly affected by a change in the amount of lightreflected by yarns or transmitted through the gaps as the fabric of theregion periodically stretches and recovers from stretch in response toat least one predetermined physiological parameter of the wearer of thegarment; and a signal processor that converts periodically varyingsignal output received from the detector or from a data acquisition unitassociated with the detector into a signal representative of the atleast one predetermined physiological parameter of the wearer of thegarment.
 2. The system of claim 1, wherein the signal processor ismounted in the garment.
 3. The system of claim 1, wherein the source andthe detector are mounted on opposing sides of the fabric.
 4. The systemof claim 1, wherein the source and detector are mounted on a same sideof the fabric.
 5. The system of claim 1, wherein the fabric includesyarns selected from the group consisting of reflective yarns,stretchable yarns, and combinations thereof.
 6. The system of claim 1,wherein the source provides radiation having wavelength(s) in the rangefrom about four hundred (400) nanometers to about eight hundred (800)nanometers; and wherein the detector responds to radiation havingwavelength(s) in the range from about four hundred (400) nanometers toabout eight hundred (800) nanometers.
 7. A method for monitoring atleast one predetermined physiological parameter of a wearer, comprising:directing radiation having wavelength(s) in the range from about 400 toabout 2200 nanometers from a source onto a region of an exterior surfaceof a fabric of a garment, said fabric having a first side defining theexterior surface and having a second side defining a wearer-contactinginterior surface when said garment is worn by the wearer, wherein saidregion defines gaps of a first size between yarns when said fabric isstretched and defines gaps of a second size between yarns that isdifferent from said first size when the fabric recovers from stretch;detecting incident radiation having wavelength(s) in the range fromabout 400 to about 2200 nanometers with a detector, to produce a signalrepresentative thereof, with said detector mounted to either the firstside or the second side of the fabric and external to the fabric,wherein the source and detector are associated with the fabric insubstantially fixed relative positions with respect to the region suchthat the reception of incident radiation by the detector at a first timeinterval when the fabric is stretched as compared to the reception ofincident radiation by the detector at a second time interval when thefabric recovers from stretch is directly affected by a change in theamount of light reflected by yarns or transmitted through the gaps asthe fabric of the region periodically stretches and recovers fromstretch in response to at least one predetermined physiologicalparameter of the wearer of the garment; and converting with a signalprocessor periodically varying signal output received from the detectoror from a data acquisition unit associated with the detector into asignal representative of the at least one predetermined physiologicalparameter of the wearer of the garment.
 8. The method of claim 7,wherein the signal processor is mounted in the garment.
 9. The method ofclaim 7, wherein the source and the detector are mounted on opposingsides of the fabric.
 10. The method of claim 7, wherein the source anddetector are mounted on a same side of the fabric.
 11. The method ofclaim 7, wherein the fabric includes yarns selected from the groupconsisting of reflective yarns, stretchable yarns, and combinationsthereof.
 12. The method of claim 7, wherein the physiological parameteris heart rate.
 13. The method of claim 7, wherein the physiologicalparameter is respiration rate.
 14. The method of claim 7, wherein thephysiological parameter is blood pressure.
 15. The method of claim 7,wherein the source provides radiation having wavelength(s) in the rangefrom about four hundred (400) nanometers to about eight hundred (800)nanometers; and wherein the detector responds to radiation havingwavelength(s) in the range from about four hundred (400) nanometers toabout eight hundred (800) nanometers.